EP2315910A2

EP2315910A2 - Installation for the in situ extraction of a substance containing carbon

Info

Publication number: EP2315910A2
Application number: EP09780723A
Authority: EP
Inventors: Dirk Diehl
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2008-08-29
Filing date: 2009-07-16
Publication date: 2011-05-04
Anticipated expiration: 2029-07-16
Also published as: RU2499886C2; DE102008044953A1; US8881800B2; CA2735300A1; PL2315910T3; WO2010023032A3; MX2011002131A; RU2011111690A; CA2735300C; EP2315910B1; WO2010023032A2; US20110146968A1

Abstract

According to known SAGD methods, an injection pipeline protruding into a deposit and at least one production pipe line leading out of the deposit are provided, superheated steam being applied to said pipelines, both as required, in order to improve the flowability of the extra-heavy oil and/or bitumen in the reservoir. According to prior art, the active region with the injection pipeline is also used for induction heating in relation to the surroundings thereof in the deposit. According to the invention, the conductor and return conductor (5, 5') of the inductor lines (10, 20; 110, 120) are guided essentially vertically in the capping (105) to the bottom of the deposit (100), at a small maximum lateral distance (a) of 10 m compared to the length of the lines, but especially less than 5 m. Preferably, the inductor lines (10, 20; 110, 120) are guided horizontally in the deposit (100) and are at different distances in certain areas. Furthermore, the electrical conductors and return conductors (5, 5') perpendicularly extending in the capping (105) preferably combine to form a conductor pair (5). In this way, the conductor pair (5) can be introduced into a single borehole (12) which reaches into the reservoir (100) and splits only once it has arrived in the reservoir (100).

Description

description

Plant for the in situ recovery of a carbonaceous substance

The invention relates to a plant for the in-situ recovery of a carbonaceous substance from an underground deposit with reduction of its viscosity. Such a device is used in particular for the production of bitumen or heavy oil from a reservoir under an overburden, as is the case with oil shale and / or oil sand deposits, for example in Canada.

For the promotion of heavy oils or bitumen from the known oil sand or oil shale deposits their flowability must be significantly increased. This can be achieved by increasing the temperature of the reservoir. If an inductive heating is used for this purpose, the problem arises that the electrical return conductor for supplying the inductors introduced into the reservoir, inadvertently also the

Heat the overburden. The heat output thus deposited in the overburden represents losses at the expense of the reservoir heater, which must be avoided.

The increase in fluidity can be done firstly by introducing solvents or diluents and / or on the other by heating or melting of the heavy oil or bitumen, for which by means of pipe systems, which are introduced through holes, heating takes place.

The most widespread and applied in situ method for the extraction of bitumen or heavy oil is the SAGD (S_team Assisted Gravity Drainage) method. In this case, water vapor, which may be added to the solvent, is pressed under high pressure through a tube extending horizontally within the seam. The heated, molten and detached from the sand or rock bitumen or heavy oil seeps to a second about 5 m deeper located pipe through that the promotion of the liquefied bitumen or heavy oil takes place, wherein the distance from the injector and production pipe is dependent on reservoir geometry.

The steam has to fulfill several tasks at the same time, namely the introduction of heating energy for liquefaction, the detachment of the sand and the pressure build-up in the reservoir, on the one hand to make the reservoir geomechanically permeable to bitumen transport (permeability) and, on the other hand, the promotion of bitumen without to allow additional pumps.

The SAGD process starts by steam being introduced through both pipes for typically three months in order first to liquefy the bitumen in the space between the pipes as quickly as possible. Thereafter, the steam is introduced only through the upper tube and the promotion through the lower tube can begin.

In the non-prepublished German patent application

AZ. 10 2007 008 292.6 with older seniority is already stated that the commonly used SAGD method can be completed with an inductive heating device. Furthermore, in the non-prepublished German patent application AZ. 10 2007 036 832.3 with older seniority described a device in which in Fig. 5 parallel inductor or electrode arrangements are provided, which are connected above ground to the oscillator or inverter.

In the older, not previously published German patent applications AZ. 10 2007 008 292.6 and AZ. 10 2007 036 832.3 is therefore proposed to superimpose the steam input with an inductive heating of the deposit. If appropriate, resistive heating between two electrodes may additionally be effected in addition. In the above-described devices, the electrical energy must always be passed through an electrical forward conductor and an electrical return conductor. This requires a considerable effort.

In the earlier patent applications, individual inductor pairs of forward and return conductors or groups of inductor pairs in different geometric configurations are energized to inductively heat the reservoir. In this case, a constant distance of the inductors is assumed within the reservoir, resulting in a homogeneous electrical conductivity distribution to a constant heat output along the inductors. Described are the spatially close together outgoing and return conductors in the sections in which the overburden ("Overburden") is pierced in order to minimize losses there.

Variation of the heating power along the inductors can, as described in the older not previously published applications, especially by sections injection of

Electrolytes take place, whereby the impedance is changed. This requires corresponding electrolyte injection devices that are expensive to integrate in the inductors or require additional costly drilling.

On this basis, it is an object of the invention to optimize the above-described device for inductive heating and to simplify in terms of energy input. In addition, the power consumption itself should be minimized.

The object is achieved by the totality of the features of claim 1. Further developments are specified in the subclaims. The invention relates to an induction-heated system in which the outgoing and return conductors for the inductor lines are guided substantially vertically and have a small lateral distance of at most 10 m. Preferably, however, the distance is less than 5 m. For this purpose, parallel bores can be present in this distance in the cover structure, so that return conductors are guided individually for this purpose. Advantageously, it is possible to start from a single borehole in which the forward and return conductors are guided together. This has the advantage that virtually no electrical power is consumed in the vertically guided area, since the electromagnetics compensate for the closely merged conductors.

In the invention, therefore, the forward and return conductors of the induction conductors can be separate, laterally side-by-side guided lines. You can also form stranded cables and especially coaxial cables. In particular, such coaxial cables can be guided in a closely matched wellbore.

In particular, in the latter embodiment, a branch (so-called Y-junction) is present at the end of the merged lines. The outgoing, horizontally guided inductor lines can run in the same direction but also in opposite directions.

In an inventive development, the inductor lines running horizontally in the deposit can have different distances in regions. In particular, it can

Losses are avoided by in turn, in areas where no inductive heating is necessary and / or desired, the lines are guided closely parallel, so that no unnecessary heating power is consumed. In the invention, a wide variety of feature combinations or possibilities of an inventive development arise. The essential further developments are listed below in detail:

1. The combined in a pair of lines vertically extending forward and return conductors can - as already mentioned - advantageously in a single hole, which reaches down to the reservoir, bring first to branch in the reservoir ('Y-junction'). In this case, the return conductor pair can be made stranded or coaxial and isolated individually or together - in a continuous insulation. The use of a single borehole, which extends into the reservoir, is also possible for several pairs of return / return conductors.

In addition, with the invention, a specialized, optimized to the respective section embodiment of the conductor arrangement is possible. In this case, a first section - from the oscillator to the branch - can be designed with particularly low losses, for example by means of HF stranded conductors, with a possibly reduced requirement for temperature resistance. A second section is formed by the single-insulated conductor acting as an inductor. In this case, increased mechanical requirements for installation and increased thermal requirement for operation must be taken into account, while low ohmic conductor losses are secondary. A third section is formed by the electrode, a non-insulated conductor end, which due to its length and z. B. by means of surrounding salt water has a low contact resistance to the reservoir. Such measures ('saline injeeted regions at non-isolated tips') are known and thus represent a low-impedance grounding. In order to prevent the accumulation of the inductive voltage drop along the entire conductor length, a compensated conductor with a resonant conductor system and a series resonant circuit - as described in the above-mentioned earlier patent applications - is also advantageously used here.

The use of compensated conductors is mandatory in the section of the inductor lines routed in the reservoir due to its length and the usually large distance (> 5 m) between the inductors. In sections I and III u. U. be waived on compensated conductors, if the sections are short (<20 m) or the distance between the return and return conductors is very low (<0.5 m). Very small distance, and associated low inductance of the line section is particularly in stranded or coaxial forward and return conductors.

2. Power generators are needed in the invention. A favorable embodiment of power generators in the considered frequency range are power converters - as described in detail in the above-mentioned German patent application AZ 10 2007 008 292.6. In addition to the power at the fundamental frequency (switching frequency), converters deliver considerable proportions of higher harmonics, ie power at integer multiples of the fundamental frequency. In the context of the present invention, it is proposed in a specific refinement to operate several adjacent pairs of return / return conductors, which are predominantly resonant at the fundamental frequency, and some which are resonant in the case of harmonics, to operate in parallel on one or a group of inverters, so that the power of the inverter is also used at the higher harmonics. Because of the immediate proximity of the entry points, the multi-lateral boreholes are particularly suitable for this purpose. 3. It is essential in the invention, the assignment and design of the inductor. The single compensated inductor consists of sectionally repeating, capacitively coupled conductor groups whose inductance and capacitance coverings and length determines the resonance frequency. In the present context, such conductor cross-section configurations are proposed whose current density distributions on both conductors are rotationally symmetric or approximately rotationally symmetrical to the inductor axis. This is already the subject of the earlier unpublished patent application of the applicant AZ 10 2008 012895.4.

4. Alternatively, the two end-grounded inductors can diverge in different, for example, opposite directions. Furthermore, it is proposed to continue the inductor arrangement periodically in the x-direction and / or periodically in the y-direction. In a specific embodiment of the invention, it is proposed to make the current amplitudes and phase position of adjacent generators adjustable, for which purpose an array of inductor lines and generators is suitable.

5. The array of inductors according to item 4 is suitable for heating the reservoir over a large area. According to the invention, it is proposed to arrange a plurality of injection and production tubes perpendicular to the orientation (and below) of the inductors. As a result, the inductors do not generally have to run parallel to the production and injection tubes, but rather oriented at an angle, in particular perpendicular to the production tube - ie. in the transverse direction. This allows a variation de heating power along the production pipes and in particular an early start of delivery, since at the intersections of inductors and production pipes, the distance between these is very low. The vertical orientation is only the special case.

The same advantages already arise under smaller angles between inductors and production pipes. 6. If cooling of the inductors by means of z. Salt water is not required, salt water can alternatively be introduced by means of vertical bores to the inductor ends to be ground, ie electrode sections. Furthermore, cooling medium and electrolyte (salt water) may be different liquids. The cooling medium can circulate in the inductor (eg, coaxial outflow and return lines for the cooling medium) and be circulated in a closed cooling circuit with a heat exchanger. Please refer to the earlier application AZ 10 2007 008 292.6.

7. The Salzwasserinjektion for better grounding a row of an inductor array according to Pkt.6 can alternatively be done by means of a locally slotted tube, which is introduced through a horizontal bore and oriented perpendicular to the inductors, for several inductors together.

Alternatively, in the context of the invention, the electrode sections can also be led into water-bearing layers outside the reservoir (above or below) in order to realize a connection with good electrical conductivity to the surrounding soil, which is possible with less expenditure on equipment. In many cases, water-bearing layers are contained in over- and / or underburden.

In an inventive development, it is further proposed to vary the distance between the forward and return conductors of a capacitively compensated inductor within the reservoir in sections. The change in distance causes sections of different inductance of the double line. It is proposed to compensate for the variation of the inductivity coating by means of adapted resonance lengths and / or by adapted capacitance layers, for example by different dielectric thicknesses, at constant resonance lengths. It is also possible to compensate for the variation of the inductance coating by a combination of capacitance change and adaptation of the resonance lengths. The laying of distance-optimized inductors in the reservoir can now be adapted to the geological conditions in the reservoir already at the beginning of the promotion. It may optionally be done as a retrofit for existing already promoting production and Dampfinjektionsrohrpaare.

The laying of a distance-optimized inductor can also be done in addition to existing inductors. In this case, an electrical connection can be made with outgoing or return conductors formerly laid inductors, the operation in the series resonance can be done by frequency adjustment on the generator / inverter. The variation in distance can take place in the vertical and / or horizontal direction, which makes it possible to adapt the heating power distribution to the reservoir geometry.

With the latter inventive development advantageously results in a homogenization of the heating power along the inductors for sections different electrical conductivities by adjusting the distance. In this case, a Induktorverlegung done so that large-scale steam chambers horizontally and / or vertically dodged.

The indicated inventive development is a

Avoiding the penetration of the often formed at the beginning of the injection tube steam chamber by displaced forward or and / or at a stunt angle as 90 ° downwardly extending inductor possible. Optionally, the installation of the oscillator in the end region of the injection and production pipe pair can take place.

The new plant has considerable advantages over the plants or devices previously known from the prior art and also in comparison to the plants or devices described in the earlier, unpublished patent applications. These are in detail: To 1: The magnetic fields of the oppositely energized forward and return conductors are almost completely compensated so that only small eddy currents are induced in the immediate vicinity of the overburden ("overburdening") and thus the power loss is drastically reduced. The coaxial design of the forward and return conductors from the power loss view is ideal, but requires increased effort at the junction. In the coaxial arrangement, the environment is completely field-free. In particular, this also permits the use of electrically conductive and magnetic materials (steel) for covering the return / return conductor pair or a lining of the bore with steel pipes in the section of the conductor pair. Furthermore, a hole is saved. Furthermore, the emission of electromagnetic waves is considerably reduced and the shielding of the oscillator at the entry point is made more compact or easier, which reduces the exposure range in which no operating personnel may reside.

To 2: There is a considerable saving in drilling while maintaining the advantage specified in point 1. The required drilling technique has been developed in the meantime and is known as 'multi-lateral drilling'. Furthermore, an oscillator can be operated alternately at different inductors due to the spatial proximity, or several oscillators at times, z. B. in during the preheating, be connected to an inductor. Again, the shielding effort is reduced when multiple oscillators can be operated in a screen cabin.

To 3: The grounding of the conductor ends leads to electrical closing of the conductor loop, without a direct electrical connection of the conductor ends is necessary. Thus, the ladder configuration requires no special drilling techniques, but comes with the existing standard drilling techniques. The isolated inductor section holds the current in the conductor and prevents premature shorting across the reservoir, which allows a uniform loss distribution along the inductor. One can represent the loss distribution, which can be determined by 3d-EM simulation, in the plane on the depth of the inductor. In a specific example (10 kHz, 707 A rms), the losses introduced into the ground are as follows: 0.3% for the return conductor pair (section A), 96.5% for the inductor (section B) and 3.2 % around the conductor ends (section C).

Ad 4: This avoids wavelength effects that would otherwise lead to variations in the current along the conductors and thus to a corresponding variation in the power dissipation density.

Re 5: The power in the higher harmonics of the inverter generators can be used for reservoir heating, which would otherwise be incurred as losses in the inverter and could even destroy it.

To 6: The rotationally symmetric current distribution provides, in the event that there is no current density in a certain radius around the inductor axis, a field-free Induktorinneres that for passing the salt water or mechanical reinforcement of the inductor by z. B. a steel cable can be used without causing eddy current losses occur in salt water or steel rope, i. without further heating of the inductor occurs.

7: In the case of diverging inductors as well as continuation in the x-direction and parallel injection and production tubes, the inductor length only needs to be a fraction of the length of the tubes, which during manufacture, installation (maximum insertion length is of stiffness of the tube) Depending on inductors and possibly less than tubes) and operation (reduction of the voltage requirements to the generators and reduction of pressure requirements for salt water injection) is advantageous. The adjustability of the phase Senlage the generators relative to each other allows the influence of the return currents through the reservoir and thus the power loss density distribution in the reservoir.

To 8: The induced by the inductors electric fields parallel to these and thus in the proposed orientation perpendicular to the injection and production tubes. Thus, a substantial inductive decoupling of inductors and tubes can be achieved, which stresses on the tubes, eddy current heating in the immediate vicinity of the tubes and the influence or disturbance of electrical equipment (such as sensors) are prevented in / at the tubes or at least greatly reduced ,

To 9: The manufacturing and the reliability of the inductors are simplified, if no device for salt water line must be provided. On the other hand, the number of additional (vertical) holes needed to inject saltwater is reduced when the electrode sections are densely packed.

10: The preferred combination of electrical return conductor and insertion into a bore saves considerable drilling costs in practice.

It can be produced in sections adapted Heizleistungsstärke. In the predominantly vertical sections, the return and the return conductors are close together. This can be very low inductive heating in the surrounding cover layer ('Overburden'), for example, only 2.5 W / m

(Fig. 5: Table Row 1, Distance 0.25 m), which is desirable because heating of the top coat is not intended. In Sections 2 to 7, the return and return conductors are routed at different distances, so that the heating power can be adapted to the respective section. The larger the distance, the higher the heating power per length. In Table (Figure 5) are heating powers for a typical reservoir is listed for different distances from the return conductor, which results when energized with 825 A (peak) @ 20 kHz. Today's drilling technology allows the distances to be reduced to 5m, whereby a variation of the heating power in the considered reservoir by a factor of 80 can be achieved (111 W / m with 5 m distance, 8874 W / m with 100 m distance) with the same current the sections, which is mandatory due to the series connection. This makes it possible to carry out a heating capacity which is adapted in sections to geological and conveying conditions of the reservoir.

In the table below, the inductance pads of a double lead from the forward and return conductors of the inductor are specified. These vary depending on the distance. The influence of different reservoir conductivities is very low. The inductor as a whole constitutes a series circuit of series resonant circuits. A series circuit is formed by the line section having the resonant length. Ideally, all series circuits are resonant at the same frequency.

Thus, the lowest voltages along the inductor are obtained. Sectionally varied distances lead in inductors constant resonant length to partially incomplete compensation, resulting in increased demands on the dielectric strength of the dielectric between filament groups, which in the worst case can lead to breakdowns and destruction of the inductor. Remedy is to be created by the resonance length and thus the capacity of this section are adapted to the existing inductance there.

In the invention, the capacitance coating can advantageously be easily adapted to the respective inductance coating, which in turn can be set in sections, the same resonant frequency without changing the resonance length. Even with a combination of the latter measure, the goal of minimum voltage requirement can be achieved in sections. If the geological conditions in the reservoir are well known, the inductor laying can be carried out with intervals adjusted in sections to the heating power demand. This can be done practically at the same time as the introduction of the steam injection and production pipes for SAGD, so that the inductive heating is already available for the preheating phase.

The following procedure can also be advantageous: The SAGD process is initially run for a few months or years without EM support. The steam chambers are already formed. Vapor chamber expansion variations along the steam injection and production pipes are generally undesirable as they may result in vapor breakthrough in individual sections ("steam breakthrough region") .When such vapor breakthrough occurs, and circumstances may do so in the remainder Portions of the reservoir still remaining bitumen (Steam to OiI Ratio (SOR) <3) are promoted, which can be associated with large financial losses.Such losses can be avoided if long before a steam breakthrough, the inductive heating to regulate the For this purpose, the distance-optimized inductor laying can be carried out, adapted to the inductive additional heat output that is required in some sections.This retrofit solution can be used to achieve the yield of existing SAGD fields.

In the specific embodiments with the associated figures below, the inductors are shown within the reservoir at the same depth and the change in distance is accomplished exclusively in the horizontal direction. Laying the return conductor of an inductor can also take place at different depths if the resulting heat output distribution and / or the laying of the inductor lines becomes more favorable, for example due to lower drilling costs which may arise due to softer rock formations or other geological boundary conditions , If there are sections of different electrical conductivities in the reservoir, then the heating power density can be homogenized by adjusting the inductor distance. An example is given in the table. Should

4 kW / m in a reservoir section with a specific resistance of 555 ohm * m, the inductor spacing must be 50 m in this example geometry. If the electrical conductivity in another section of the reservoir is only half, then the inductor distance is up

67 m increase, in turn, to bring in 4 kW / m heating power.

In certain sections, return conductors can advantageously be kept close together, if only low heating power densities are required there. So run forward and return conductors possibly through the steam chamber and the prevailing high temperatures (eg, 200 ⁰ C) exposed, which can lead to premature aging of the inductor, thereby reducing the service life. This can be avoided if, as shown in Section VI, the area of the steam chamber is bypassed horizontally and / or vertically.

In many cases, in the SAGD process at the beginning of the horizontal section, the vapor chamber grows faster than in the more upstream sections, since the vapor temperature near the point of introduction is the hottest and the vapor pressure is highest. This often leads to the formation of a large steam chamber. Therefore, it may make sense to do without an additional inductive heating there, also to avoid premature steam breakthroughs. For this purpose, the oscillator can be moved forward, so that the inductor does not need to go through the steam chamber at the beginning. The same can be achieved if the inductor is guided downwards at a more obtuse angle if the oscillator is to continue to be installed near the injection and production tubes. It is advantageous that inductor length and associated drilling costs can be saved. Furthermore, the premature aging of the inductor in the region of the first steam chamber is avoided.

In the invention inductor arrangements are possible in which the loop is closed underground, which can be done with advanced drilling techniques. The oscillator can be installed as shown in the end of the pipe pair or as in the previous figures in the vicinity of the beginning of the tube pairs (so-called Well-Heads). The submerged conductor loop with recess in the steam chamber saves inductor length and thus costs.

Further details and advantages of the invention will become apparent from the following description of exemplary embodiments play with reference to the drawing in conjunction with the claims.

Each shows in schematic and partial perspective view

1 shows an oil sand deposit of several elementary areas with a plurality of conductor arrangements for inductive reservoir heating and a conveyor pipe, FIG.

FIG. 2 shows a conductor arrangement for inductive reservoir heating with grounded inductors,

3 shows an arrangement according to FIG. 2 with sectionally different distances of the inductor lines, FIG. 4 shows the plan view of an inductor arrangement according to FIG. 3 with eight sections of different conductor spacings, FIG. 5 shows the schematic structure of a compensated inductor with distributed capacitances,

FIG. 6 shows the cross section of a multifilament conductor with two filament groups, 7 shows a plan view of an arrangement with a large-scale steam chamber at the beginning section of the injection tube and an oscillator position displaced therefrom, FIG. 8 shows a plan view modified from FIG. 7 with oscillator position in the end region of the tube pair and the conductor loop closed underground;

FIG. 9 shows an arrangement for inductive reservoir heating with inductors running and grounded in opposite directions

FIG. 10 shows a detail of a two-dimensional inductor-oscillator array with electrode sections that have been merged in sections for the purpose of grounding.

In the individual figures, the same elements have the same or corresponding reference numerals. The figures are partly described together.

In the three-dimensional representations of a seam with oil reservoir according to FIGS. 1 to 3 and 6, 9 and 10, 100 each means one elementary unit of the reservoir, which is considered in each case for the individual descriptions of the other figures. Such elementary unit is arbitrarily repeatable in both horizontal directions of the seam.

The latter can be seen, for example, from FIG. 1: An underground oil sands deposit (seam) forms the reservoir, with elementary units 100 of a length 1, height h and thickness w being obtained one behind the other or next to each other. Above the reservoir 100 is an overburden layer 105 ("overburden") of thickness s. Corresponding layers ("underburden") are located under the reservoir 100, but are not marked in detail in FIG.

In the known SAGD method, at the bottom of the reservoir 100, substantially one above the other, an injection pipe for introducing steam, by means of which the viscosity of the bitumen or heavy oil is lowered, and a conveying or spraying production pipe available. The production pipe is designated 102 in FIG. 1, while an injection pipe is not shown here and, if necessary, also superfluous. It has already been proposed to provide 100 lines and / or electrodes for the electrical heating of the reservoir. Especially for inductive heating, the lines are designed as inductor lines 10, 20 in FIG. The inductor lines 10, 20 are guided in the reservoir 100 at a predetermined distance ai substantially parallel and horizontal.

It is essential in FIG. 1 that production tube 102 and inductor lines 10, 20 do not run in the same direction, but in particular form a right angle. Other angles, i. Orientations of inductor and production pipes exist. This allows for the geological boundary conditions.

Each of the repeating units 100 is assigned an oscillator unit 60, 60 ',... As an over-the-day RF power generator, from which the electrical power is generated and fed via the forward and return conductors into the inductors. For this purpose, the return and return conductors must be routed vertically through the overburden into the reservoir. If the distance a ₂ of the forward and return conductors in the vertical range is as low as possible and al> a2 applies, no heating takes place and energy is saved.

In Figure 1 for two holes 12, 12 'are present, which have a distance of less than 10 m. This is small in comparison to the dimensions of the reservoir and in particular the length of the inductor lines 10, 20. In one bore, the forward conductor and in the other bore of the return conductor is guided, wherein in the reservoir at the transition to the inductor lines widening to a multiple distance is carried out.

Instead of in separate parallel holes return conductor can also be performed in a single bore, which there is the possibility of an even smaller distance. In a single borehole, the forward and return conductors can be stranded together or form a coaxial cable, which is branched in the reservoir.

FIGS. 1, 2 and 6 to 8 each show a coordinate system with the coordinates x, y and z, which facilitates the mining orientation. The coordinate system can also have a different orientation.

Specifically, with reference to FIG. 2, it is illustrated that underneath the ground first an area 105 with overburden, then a deposit with a reservoir 100 of bitumen and / or heavy oil and below an oil-impermeable area 106, the so-called basement, follow. Such soil or rock formations are typical of oil shale or 01 sand deposits.

According to FIG. 2, an oscillator 60, which is used as a high-frequency generator for days, supplies electrical energy to the generator

Deposit 100 brought in. For this purpose, a single vertical bore 12 is present in this case, which extends into the region of the reservoir 100 and there passes into two horizontal holes, which are not marked in detail. From outside the overburden there are further provided means for introducing salt dissolved in water (so-called saline) which have suitable conductivity properties.

In the vertical bore 12, a pair of conductors with a common electrical return conductor 5 is introduced, wherein the end-side ends of the forward and return conductors are connected to the oscillator 60 as an energy converter. The other ends extend to the reservoir 100.

Upon reaching the reservoir 100, the forward / backward branch

Return conductor pair 5. For this, a so-called Y-branch 25 is present. Starting from the Y-branch 25, the inductor lines 10 and 20 run horizontally in the reservoir 100 parallel in the reservoir 100 and into the region of the saline-injected region in which the conduits 10 and 20 are not insulated and act as electrical inducers. In particular in the area of the inductor lines 10, 20, the induction heating should thus be formed.

With such a device, the power loss is significantly reduced, since the magnetic fields of the guided at a short distance opposite energized forward and Rücklei- ter almost completely compensate in the area A. The combined return conductor pair may be formed, for example, as a coaxial line 5. In particular, in the coaxial arrangement, the environment of such a pair of conductors is completely field-free. This then allows the use of electrically conductive and magnetic materials for a sheathing of the forward / return pair or a border of the vertical bore 12 with steel pipes.

The formation of the Y-branch 25 is carried out in an electrically known manner, which is not discussed in detail in the present context.

Since the radiation of electromagnetic waves in the region of the vertical borehole 12 is considerably reduced, the shielding of the oscillator 60 at the entry point can be made more compact. This proves to be advantageous for the so-called exposure area, in which no operating personnel may stay.

In the figures, the actual production pipe is indicated by 102. This is conventionally designed in accordance with the prior art such that the liquefied bitumen collects therein, whereafter it is sucked off in a known manner.

At the end of the two conductors 10 and 20 results in accordance with Figure 1 each have a substantially cylindrical salzbeeinflusster area 11/12, which is for the electrical conductivity and thus the inductive heating effect of particular importance. It will Thus, the effect of a low-impedance grounding of the inductors achieved without these need to be connected to each other via a separate conductor loop under or over days.

Overall, therefore, three areas are formed in FIG. 2:

The lines 10/20 from the oscillator 60 to the branch 25 form a first section A, in the reservoir 100 a second section B and in the end region a third section C. Advantageously, different conductor arrangements can be selected in the individual sections A, B and C. , For example, stranded conductors are used in the first section A. In the second section B, on the other hand, insulated insulated conductors ("isolated single conducors") are used for the inductor leads, whereas in the third section C non-insulated conductor ends are present which form electrodes.

In FIG. 3 it is shown that with an arrangement according to FIG. 1, induction lines 10 and 20 guided in this case need not run parallel. Rather, they have different distances a _lr which can be adapted to the conditions of the deposit. Depending on the geological conditions, they can have sections for an inductive interaction with each other and be kept very narrow there, so that their fields compensate each other. In particular, in the event that a gas bubble 30 is present in the deposit 100 by the vapor input by means of SAGD method, which represents a so-called "deaf" area and / or which is already exploited, there can be the parallel arrangement of the lines 1 / 20 around this vapor bubble area are guided around tightly and widen again behind the vapor bubble 30 in order to generate the inductive heating effect.At the end, in turn, results in a known manner a conductor loop, which is particularly closed above ground, which is easy to achieve manufacturing technology. A corresponding plan view of such an inductor arrangement is shown in FIG. 4. In this case, a total of eight sections I, II,..., VIII are entered at different distances a _{x of} the inductor lines 10/20. It should be noted that for the sections I, II,..., VIII separately individual compensation measures of the lines are carried out taking into account the changed resonance lengths.

The following table shows the inductance coverings of a double cable, ie the return conductor of the inductor. As mentioned, these vary depending on the distance a _x between about 0.46 and 1.61 μH / m. The influence of different reservoir conductivities is very low. The inductor as a whole represents a series connection of series resonant circuits.

A series circuit is formed by the line section having the resonance length L _R. Ideally, therefore, all series circuits would be resonant at the same frequency. This would give the lowest possible voltages along the inductor. Sectionally varying distances, however, lead in the case of inductors of constant resonance length to partially incomplete compensation, which leads to increased demands on the dielectric strength of the dielectric between filament groups. Under certain circumstances, it may otherwise lead to breakdowns or even to the destruction of the inductor.

Remedy can be created by the resonant length and thus the capacity of this section are adapted to the present there inductance in the individual sections. Table :

Column 1 of the table shows the distance of the induction lines in m, in column 2 the resistivity of the reservoir in m, in column 3 the applied electric power in W / m, n column 4 and the inductance in μH / m (analytically and by FEM calculated) and in column 6, the resonance length in applied for an oscillator frequency of 2OkHz.

It can be seen that with increasing distance of the inductor, the Heizleistungsrate increases as electrical power loss. Conversely, this results in that only a small power loss occurs at comparatively small distance of the inductor, since the electromagnetic fields - as in the vertically guided return conductor pair 5 - compensate as far as possible for near-adjacent lines and thus no inductive heating effect. This effect can be exploited if necessary. Similarly, the resonance length L _{R of} the line changes, which must be adjusted accordingly, as shown in detail in the earlier application AZ 10 2007 008 282.6. In the table, therefore, the resonance lengths adapted for the respective distance of the return conductor are listed so as to obtain, in sections, the same resonant frequency, for example 20 kHz. The relative change in resonant length is proportional to 1 / sqrt (inductivity coating). This means that the resonance length in the vertical sections inductor distance of z. B. 0.25 m is about twice as large as a nominal inductor distance of 100 m. Corresponding changes result, for example, at a resonant frequency of 100 kHz. Specifically, resonant frequencies between 1 and 500 kHz are considered suitable, with 10 kHz on the one hand and 100 kHz on the other.

As already mentioned in the introduction, the compensation of the inductor lines is the subject of the earlier patent application AZ 10 2007 008 282.6 and has already been described there in detail, to which reference is expressly made here. In particular so-called multifilament conductors according to FIG. 5 can be used for this purpose, to which in turn reference is made to the earlier patent application AZ 10 2008 036 832.3.

In the latter context, reference is made to FIGS. 5 and 5: FIG. 5 shows the schematic structure of the compensated conductors for the inductor lines with distributed capacitances, and FIG. 6 shows the cross section along the line VI-VI. The lines are formed of conductors 51 and 52, which form according to Figure 6 multifilament cables within an insulation 53. The resonance length L _R can be adapted to the sectionally changing spacing of the inductor lines.

With reference to FIG. 7, it is made clear that, in the case of an arrangement according to FIG. 2, a steam chamber 30, for example designed to be particularly large, can be present at the beginning section of the injection pipe. In this case, it is recommended that the oscillator position, ie the generator 60, for days move or even in the end of the conductor pair 10/20 to arrange. The lines are closed in this case with an underground conductor loop 15, which may also be located directly behind the steam bubble.

FIGS. 7 and 8 show corresponding schemes as a plan view. From these two figures it is particularly clear that the inventive concept is also suitable for retrofitting existing bitumen or heavy oil conveying systems. In practice, certain areas of Ölsandla- gerstätten have already been exploited by the known SAGD method, which form in the already exploited areas usually large vapor bubbles. By means of a device having a "mobile" high-frequency generator 60, it is possible to displace and to shift the inductor arrangement away from the starting section of the injection / conveying tube device In this case, the inductor conductor loop is advantageously always closed underground

FIG. 9 shows an arrangement in which, according to FIG. 1, a vertical bore 12 is present approximately in the middle of the illustrated reservoir 100. At a local oscillator 60 there is again a pair of conductors 5 in the

Vertical bore 12 introduced. Upon reaching the deposit 100, such a branch 25 is now present, in which the horizontal conductors 110, 120 run diametrically in opposite directions-that is to say with an increasing distance-and are in each case earthed via electrodes 111 and 121 there.

The corresponding distribution of the heating power in this geometry was also calculated for this case by means of FEM (Finite Element Methods) and gave satisfactory boundary conditions. It is also possible with such a routing of the inductor lines, the non-insulated conductor ends out of the reservoir out in areas of higher electrical conductivity. For example, water-bearing strata can be found outside the reservoir, for example in the overburden or underburden.

Finally, FIG. 10 shows a modification of a system according to FIG. 1b with arrangements according to FIG. 9, in which a two-dimensional 200 is formed from individual inductors. The inductors are shown with diverging lines one behind the other and in two rows next to each other. Two deposits of oscillators 60, 60 ', 60 ", ... are present in each case over the deposit 100, of which pairs of conductors 5, 5', 5",... Are perpendicular through the overburden to the deposit 100 extend and branch off via corresponding rows of branches 25, 25 ', 25' ', ... in opposite directions.

By counter-switching such arrangements, the power loss can be minimized and thus optimize the converted heat output.

Specific to the two-dimensional array shown in Figure 10 is that it consists of a plurality of antennas, which are specifically formed in Figure 10 by the individual inductor pairs 110 _1D / 120 _1D , which can be controlled individually by current amplitude and phase. For this purpose, each inductor pair is assigned its own generator from the group of the generators 60 _1D shown in FIG.

Overall, it should be noted that now the forward and return conductors of the inductor in the overburden are guided substantially vertically to the depth of the deposit and in comparison to the longitudinal extension of the lines have a low lateral distance a of at most 10 m, but in particular less than 5 m. Preferably, the inductor lines are in led the deposit horizontally and regions have different distances, whereby the power distribution is changeable. If the vertical outward and return conductors running vertically in the overburden are combined to form a line pair, the line pair can be introduced in a single bore which reaches down into the reservoir and can only be branched in the reservoir. In the overburden then no power losses.

Claims

claims

1. An installation for the in situ recovery of a hydrocarbonaceous substance from an underground reservoir via at least one production pipeline leading out of the reservoir, in particular for the production of bitumen or heavy oil from a reservoir under an overburden, reducing its viscosity, wherein the production pipeline in the deposit means for induction heating are associated with the environment of the production pipeline, which include a high-power electrical generator outside the overburden and reservoir, an electrical return conductor and inductor lines connected thereto, characterized in that the outward and return conductors (5 ) of the inductor lines (10, 20, 110, 120) in the overburden (105) to the depth of the deposit (100) are guided substantially vertically and compared to the longitudinal extension of the lines a small lateral distance (a) of at most 10 m, esp but less than 5 m.

2. Plant according to claim 1, characterized in that the return conductor (5) for the two Induktorleitungen

(10, 20, 110, 120) are guided in parallel holes (12, 12 ') with a distance of at most 10 m.

3. Plant according to claim 2, characterized in that in the parallel bores (12, 12 '), the outgoing and return conductors

(5) for the two Induktorleitungen (10, 20, 110, 120) are guided as capacitive compensated lines.

4. Plant according to claim 1, characterized in that the outgoing and return conductors (5) for the two Induktorleitungen

(10, 20, 110, 120) have a maximum lateral distance of 0.25 m and are guided in a common bore (12).

5. Plant according to claim 4, characterized in that the common bore (12) has a diameter <0.5 m, in which the return conductor (5) for the two inductor lines are guided closely next to one another at a distance.

6. Installation according to claim 5, characterized in that the outgoing and return conductors (5) for the two inductor lines (10, 20, 110, 120) are insulated from each other and form a common line.

7. Plant according to claim 5 or 6, characterized in that the return conductor (5) in the bore (12) against each other or are stranded together.

8. Plant according to claim 5 or 6, characterized in that the return conductor (5) in the bore (12) form a coaxi- line.

9. Installation according to one of the preceding claims, characterized in that in the single bore (12) a plurality of pairs of conductors (5 _X ) out of return conductor for the Induktorleitun- conditions (10 _± / 20 _x , 110 _± / 120 _x ) out are.

10. Installation according to one of claims 6 to 8, characterized in that the combined line pair (5) from the forward and return conductors for the inductor (10, 20) in the reservoir Reservoir (100) is branched.

11. Plant according to claim 10, characterized in that for branching a so-called Y-junction (25) is formed.

12. Installation according to one of the preceding claims, characterized in that from the oscillator (60) to the reservoir (100) a first portion (A), in the reservoir a second section (B) in the reservoir and in the end region with conductor loop (15) and or saline (11, 21) a third section (C) is formed.

13. Plant according to claim 7 or 8, characterized in that in the individual sections (A, B, C) each have a Different structure of the conductors (5, 10, 20, 11, 21, 110, 120) are selected.

14. Plant according to claim 14, characterized in that in the first section (A) stranded conductor for the forward / return pair

(5) can be used.

15. Plant according to claim 13, characterized in that in the second section (B) for the inductor lines (10, 20; 110, 120) effectively insulated conductors ("isolated single conductor") are used.

16. Plant according to claim 13, characterized in that in the second section (B) for the inductor lines (10, 20; 110, 120) capacitively compensated conductors are used.

17. Plant according to claim 13, characterized in that in the third section (C) non-insulated conductor ends are present, the electrodes (11, 21) form the saline area.

18. Plant according to claim 17, characterized in that the electrodes (11, 21) together with salt accumulations form an electrical loop.

19. Plant according to claim 17, characterized in that the non-insulated conductor ends (11, 21) from the reservoir (100) in layers of higher electrical conductivity, for example, to water-bearing layers outside of the reservoir (100) are performed.

20. Plant according to claim 15, characterized in that at the end of section A, the inductor lines (110, 120) extend in the same direction.

21. Plant according to claim 15, characterized in that at the end of section A, the inductor lines (110, 120) extend in the opposite direction.

22. Installation according to one of the preceding claims, characterized in that in the reservoir (100) horizontally extending inductor (10, 20, 110, 120) with each other partially different distances (a _x ) have.

23 Plant according to claim 22, characterized in that at the inductor lines (10, 20, 110, 120) in the reservoir (100) sections (I - VIII) are formed with an adapted resonance length (L _R ), such that all sections at the same Frequency are resonant.

24. Installation according to claim 22, characterized in that "pigeon" or exploited areas of the deposit (100), for example areas with a vapor bubble (30), by the inductor ducts (10, 20, 110, 120) are each bypassed in pairs become .

25. Installation according to claim 24, characterized in that the two inductor lines (10, 20, 110, 120) are tightly guided in the bypassed area and thus their electromagnetic fields are compensated and the heating power input is low.

26. Installation according to one of the preceding claims, characterized in that an array (160) of conductor pairs (11Oi,

12O ₁ ) and power generators (60ij).

27. Installation according to claim 26, characterized in that each power generator (60ij) a pair of conductors (11Oi, 12O ₁ ) is assigned.

28. Plant according to claim 26, characterized in that the array (160) with the orientation of the line pairs (110, 120) at a predetermined angle to the direction of the conveyor tubes (102 _x ), in particular transversely thereto, is arranged.

29. Installation according to one of the preceding claims, characterized in that a power generator (60) for a plurality of line pairs (11Oi, 12O ₁ ) is used.

30. Plant according to claim 26, characterized in that the power generators (6O ₁₁₁ ) of the array (160) are switchable.

31. Installation according to one of the preceding claims, characterized in that the power generators are high-frequency oscillators (6O ₁₁₁ ) which generate electrical power with frequencies between 1 and 500 kHz

32. Plant according to claim 31, characterized in that the frequency is about 10 kHz.

33. Plant according to claim 31, characterized in that the frequency is about 100 kHz.